There is a three-dimensional picture system that provides a three-dimensional display in which a right eye picture and a left eye picture, which have a parallax between left and right eyes, are provided to left and right eyes an observer wearing three-dimensional eyeglasses. Particularly, a three-dimensional film in which a picture is projected on a large screen can provide entertainment to audiences using films that are very popular.
Generally, when showing a foreign film, subtitles of a mother language may be provided. In some regions, subtitles of two or more languages may be necessary. In recent years, for hearing-impaired people, there has been an increase in case of displaying conversation contents or voice information with subtitles of a mother language even in a domestic film. On the other hand, some observers viewing films think that subtitles are unnecessary. Thus, requests for additional information such as subtitles have become diverse when a great many people simultaneously view one picture.
Even in the case of a picture that is very popular, similarly, displaying additional information such as subtitles is requested. However, the insertion of subtitles into a three-dimensional picture that uses two types of pictures, namely, a picture for a right eye and a picture for a left eye, increases complexity.
Visual fatigue occurs more easily in three-dimensional viewing of text information such as a subtitle than in three-dimensional viewing of a natural image. For example, when a head tilts, a subtitle seen by the right eye and a subtitle seen by the left eye are shifted up and down. In this case, binocular fusion of the subtitle of the right eye picture and the subtitle of the left eye picture becomes difficult, causing visual fatigue. A degree of this visual fatigue is larger than that of visual fatigue that occurs due to head tilting when the right eye picture and the left eye picture are simply fused between both eyes. Thus, subtitles must be displayed only for those who need a subtitle display, and the subtitle display must be more viewable.
Patent Literature 1 discloses a subtitle display system that allows only those needing a subtitle display to utilize the subtitle display. FIG. 1 is a block diagram showing a configuration of the subtitle display system discussed in Patent Literature 1.
Referring to FIG. 1, the subtitle display system includes AV (audio and visual) controller 101, subtitle file reproduction device 102, display unit 103, show controller 104, digital audio player 105, and subtitle signal transmission means (infrared modulator) 106.
AV controller 101 supplies a control signal for reproducing a subtitle file to subtitle file reproduction device 102 via serial interface 107. An output of subtitle file reproduction device 102 is transmitted to each user's display unit 103 via subtitle signal transmission means 106 based in an infrared ray or an electric wave.
The display unit 103 includes subtitle signal reception means (infrared receiver) 124 corresponding to subtitle signal transmission means 106. Display unit 103 includes a control unit for enabling selection of a subtitle of a desired language. To enable a viewer to select a subtitle of a desired language, subtitle signals of a plurality of different languages are transmitted at different frequencies, or transmitted by multiplex transmission. The viewer can accordingly display the subtitle of the desired language by operating a selection switch (not shown) located in display unit 103. As a configuration example of display unit 103, a goggle-shaped unit mountable on the head can be used.
With such configuration and operation, without any influence on those who do not require a subtitle display, a subtitle display can be provided to only those such as hearing-impaired people or foreigners needing the subtitle display.
Patent Literature 2 discloses a display system configured to use first and second polarized lights having polarization directions set orthogonal to each other, project one of the two subtitles for foreign languages to the first polarized light and the other subtitle to the second polarized light, and select one of the subtitles by using polarization eyeglasses. FIG. 2 is a block diagram showing a configuration of the display system discussed in Patent literature 2.
As shown in FIG. 2, the display system projects a picture to screen 212, and includes light source lamp 201, polarized light separation means 202, operation input means 203, selection circuit 204, picture signal processing circuit 205, first and second picture light generation means 6P and 6S, polarized light synthesis means 207, projection lens 208, memory 211, and viewing eyeglasses 9P and 9S as polarized light viewing means.
Light emitted from light source lamp 1 enters polarized light separation means 202, and is separated into two polarized lights orthogonal to each other, namely, a P wave and a S wave. The P wave is guided to enter picture light generation means 6P, and the S wave is guided to enter picture light generation means 6S.
When a user selects the language of a subtitle by operation input means 203, selection circuit 204 supplies picture signals Pi2 and Pi2 corresponding to the selected language and subtitle signals SB1 and SB2 indicating subtitles described in the selected language to picture signal processing circuit 205. Picture signal processing circuit 205 generates synthesized picture signal Ps1 (an English subtitle) synthesizing picture signal Pi1 with subtitle signal SB1, and synthesized picture signal Ps2 (a French subtitle) synthesizing picture signal Pi2 with subtitle signal SB2.
In memory 211, a function selection menu having a plurality of languages is prepared, and graphics data of messages corresponding to the respective languages are recorded. In response to a user's request, graphics data M1 and M2 are input to picture signal processing circuit 205, and together with subtitle signals SB1 and SB2, synthesized with synthesized picture signals Ps1 and Ps2.
Picture light generation means 6P outputs picture light PP of a P wave based on synthesized picture signal Ps1. Picture light generation means 6S outputs picture light PS of a S wave based on synthesized picture signal Ps2. Picture light PP of the P wave and picture light PS of the S wave are synthesized into one synthesized picture light PC by polarized light synthesis means 207. Synthesized picture light PC is projected from projection lens 208 to screen 212.
Viewer V1 wishing to view a picture with English subtitles uses P wave viewing eyeglasses 9P to which a polarization film transmitting the P wave is bonded. Viewer V2 wishing to view a picture with French subtitles uses S wave viewing eyeglasses 9S to which a polarization film transmitting the S wave is bonded. Thus, each viewer can view a picture with the subtitle of a desired language.
Patent Literature 3 discloses an image projection system configured to project subtitle images having polarized light components of projection light modulated in a superimposed manner, and enable observation of subtitles only when the audience wears polarization eyeglasses. FIG. 3 is a block diagram showing a configuration of the image projection system discussed in Patent Literature 3.
As shown in FIG. 3, the image projection system includes information processing device 311 for processing the signal of a projected image, image projection device 312 for magnifying and projecting an image, and polarization eyeglasses 320 for observing the projected image.
Information processing device 311 includes information processing unit 314 and image signal processing unit 315. Information processing unit 314 computes an image signal to be polarized and modulated based on an image signal or image information generated from main projection data 317, and an image signal or image information generated from modulated projection data 318 projected as polarized light modulation therefor.
Image projection device 312, which magnifies and projects an image, includes a light source (not shown), image generation unit 312a, and magnification-projection optical system 312b. Polarization eyeglasses 320 formed into the shape of eyeglasses has a lens portion including a polarization plate.
Images not observed when observation is performed in a state unrelated to polarization are modulated to be superimposed by changing the ratio of two polarization components orthogonal to each other. When it is not necessary to view the images, the presence of a modulated image is not bothersome, and the modulated image can be viewed by passage through the polarization plate when necessary. For example, when a subtitle is displayed as a modulated image, only those wearing polarization eyeglasses can read the subtitle. On the other hand, those not wearing polarization eyeglasses do not sense contents thereof.